[charlie]

I grabbed a packet of WLP-007 a couple of weeks ago, and last Monday was my day to do yeast things. I sterilized 2 X 1L of starter wort to boost some WLP-001 for the upcoming Rye pale ale, and 2 X 500 ml to turn the 007 into stock starters. It was only when I prepped to pitch the 007 that I noticed the expiration date on the packet: Best By May 11, 2019. I'm usually pretty anal about not buying expired products, so I'm not sure how that happened. But, long story short, I went ahead and pitched it.

Tuesday - No sign whatsoever of yeast activity.
Wednesday - I see some krausen in the middle of the flask, and swirling the flask causes it to foam up a bit.

The 007 was 247 days past it's best by date, but it wasn't completely dead. Just mostly dead. I'm not sure what I'll do with the mess, because I don't think it's a good idea to select for the most long-lived yeast, but I'll burn that bridge when I come to it.

Charlie

[denny]

FWIW, I started up a Wyeast pack from last March in an SNS starter recently.  By the next morning there was a good layer of yeast in the bottom.  I pitched it that afternoon and 12 hours later had vigorous fermentation.  So maybe yours will be alright also.

[hopfenundmalz]

Don't give up on it. If you have a bigger jar/flask, make a bigger starter once the first is done, pour off the liquid above the yeast, pour into the second starter.

I've done that before.

[dmtaylor]

I've had terrible luck over the years with any pack of yeast older than about 8 or 9 months.  I just tried again with a 12-month pack for my last batch and it turned out sour.  Dead as a doornail.  Not going to try this too many more times anymore, it ain't worth the couple days it takes for the yeast to turn out being "dead again", or "contaminated again, aw dammit".

[charlie]

It has  been 72 hours since I pitched the 007, and at this point its performance has been less than stellar. I have a little bit of krausen, but nothing like I usually see at any point when pitching active yeast. So I'm going to pitch it down the drain. Fortunately I don't need that yeast until Feb 2, so I'm going to fuss at the LHBS to get me a fresh one.

Charlie

[goose]

My rule of thumb is no longer than 4 months.

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[denny]

My rule of thumb is no longer than 4 months.

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That rule would have me tossing out a bunch of good yeast.

[charlie]

My rule of thumb is no longer than 4 months.

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That rule would have me tossing out a bunch of good yeast.

My presonal rule, and the rule that the head brewer used at the production brewery, is four months. Yeast is a mutable organism, and my concern with the old WLP-007 is that I might be selecting for long lived yeast as opposed to yeast that made good beer. Because there is a difference!

I guess that we'll never know unless one of us gets a PCR machine and does the experiment. Until then I'm going to go with what works.

Charlie

[Robert]

Yeast is a mutable organism... might be selecting for long lived yeast as opposed to yeast that [will make] good beer...

Very good point and easily overlooked.   Something to consider when banking or repitching as well.

[denny]

Science vs experience again....just kegged a brown made with an 11 mo. old smack pack.  Hi problems with either performance or flavor.  Not the first time I've done something like that.   So my rule is you don't know til you try.

[Robert]

"Trust, but verify..."

[goose]

My rule of thumb is no longer than 4 months.

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That rule would have me tossing out a bunch of good yeast.

I don't keep a lot of yeast on hand and rarely re-pitch because of the times I brew styles that use a particular strain.  Not saying it is a bad thing to keep it around, it's just that I have better luck with a fresh pack when I brew.